A5060082494- Atmospheric aerosols and clouds
- Atmospheric chemistry and aerosols
- DNA Repair Mechanisms
- Atmospheric Ozone and Climate
- Skin Protection and Aging
- Meteorological Phenomena and Simulations
- Carcinogens and Genotoxicity Assessment
- DNA and Nucleic Acid Chemistry
- bioluminescence and chemiluminescence research
- Icing and De-icing Technologies
- CRISPR and Genetic Engineering
- Cryospheric studies and observations
- Cancer-related Molecular Pathways
- melanin and skin pigmentation
- Light effects on plants
- Atmospheric and Environmental Gas Dynamics
- Marine and coastal ecosystems
- Microbial Community Ecology and Physiology
- Wildlife Ecology and Conservation
- Polar Research and Ecology
- Photodynamic Therapy Research Studies
- Arctic and Antarctic ice dynamics
- Advanced biosensing and bioanalysis techniques
- Genetics, Aging, and Longevity in Model Organisms
- Epigenetics and DNA Methylation
Desert Research Institute
2015-2025
University of Nevada, Reno
1988-2019
Government of the Northern Territory
2019
Deschutes Research
2000-2018
The University of Texas MD Anderson Cancer Center
2006-2015
The University of Texas Health Science Center at Houston
2014
University of North Carolina at Chapel Hill
2013
Genesis Foundation
2000-2012
University of Houston
1999-2010
Temple University
2009
A modal aerosol module (MAM) has been developed for the Community Atmosphere Model version 5 (CAM5), atmospheric component of Earth System 1 (CESM1). MAM is capable simulating size distribution and both internal external mixing between components, treating numerous complicated processes physical, chemical optical properties in a physically-based manner. Two versions were developed: more complete with seven lognormal modes (MAM7), three (MAM3) purpose long-term (decades to centuries)...
Based on boundary layer theory and a comparison of empirical power laws relating the Reynolds Best numbers, it was apparent that primary variables governing hydrometeor's terminal velocity were its mass, area projected to flow, maximum dimension. The dependence velocities surface roughness appeared secondary, with apparently changing significantly only during phase changes (i.e., ice liquid). In theoretical analysis, new, comprehensive expression for drag force, which is valid both inertial...
A process‐based treatment of ice supersaturation and nucleation is implemented in the National Center for Atmospheric Research Community Atmosphere Model (CAM). The new scheme designed to allow (1) with respect ice, (2) by aerosol particles, (3) cloud cover consistent microphysics. a two‐moment microphysics code used evaluate mechanisms CAM. model able reproduce field observations mass mixed phase occurrence better than previous versions. observed patterns frequency supersaturation....
ABSTRACT Twelve species of Antarctic diatoms were studied to assess UV sensitivity in relation cellular and molecular aspects DNA damage repair. Responses cell survival, induction damage, repair capacity determined. There was a wide range interspecific UV‐sensitivity among diatoms. D 37 values (average fluence kill one cell) ranged from 681 J · m −2 (most sensitive) 25,338 resistant). Molecular analysis (by radioimmunoassay) UV‐induced [induction cys‐syn cyclobutane dimers pyrimidine (6‐4)...
Abstract— The significance of the pyrimidine(6‐4)pyrimidone photoproduct in mammalian cell killing is considered. Photochemical data indicate that the(6–4) induced at a substantial frequency compared to cyclobutane dimer and action spectra for induction both lesions are equivalent. repair of(6–4) photoproducts various normal UV‐hypcrsensitive lines, including several recently derived somatic hybrids transformants, presented. sensitivity these cells ultraviolet irradiation correlates better...
We present parameterizations of the single‐scattering properties for individual ice crystals various habits based on results computed from accurate light scattering calculations. The projected area, volume, and with shapes sizes are 56 narrow spectral bands covering 0.2–5 μm. crystal considered in this study hexagonal plates, solid hollow columns, planar spatial bullet rosettes, aggregates that commonly observed cirrus clouds. Using observational relationships between aspect ratios crystals,...
The masses, dimensions, and habits of over 2800 natural ice particles precipitating from orographic winter storms in the central Sierra Nevada were obtained using photomicrographs. Ice that could be unambiguously classified used to generate empirical expressions relating snow particle masses dimensions. Many types had not been investigated previously. influence riming aggregation on was examined. When possible, comparisons are made between these results those other experimental observations....
The detrimental effects of elevated intensities mid-UV radiation (UVB), a result stratospheric ozone depletion during the austral spring, on primary producers Antarctic marine ecosystem have been well documented. Here we report that natural populations zooplankton also sustain significant DNA damage [measured as cyclobutane pyrimidine dimers (CPDs)] periods increased UVB flux. This is first direct evidence solar may in to organisms other than Antarctica. extent pelagic icefish eggs...
Cyclobutane pyrimidine dimers were quantified at the sequence level after irradiation with solar ultraviolet (UVB) and nonsolar (UVC) light sources.The yield of photoproducts specific sites was dependent on nucleotide composition in around potential lesion as well wavelength used to induce damage.Induction greater presence 5' flanking pyrimidines than purines; guanine inhibited induction more adenine.UVB increased cyclobutane containing cytosine relative thymine homodimers.At single UVC UVB...
Abstract Recent work on the terminal velocity of ice crystal aggregates suggests that their “Re–X” relationship may not be well predicted by current theory. This study examines possible reasons for this departure from theory, and develops a new Re–X appropriate aggregates. The methodology Khvorostyanov Curry was applied to formulate power-law expressions all particle types. Fall speed differences between approach described here were as large 50% 30% single crystals. primarily due following:...
High mobility group protein B1 (HMGB1) is a multifunctional with roles in chromatin structure, transcriptional regulation, V(D)J recombination, and inflammation. HMGB1 also binds to bends damaged DNA, but the biological consequence of this interaction not clearly understood. We have shown previously that cooperatively nucleotide excision repair damage recognition proteins triplex-directed psoralen DNA interstrand cross-links (ICLs). Thus, we hypothesized modulates mammalian cells....
Abstract. Normal human skin fibroblasts were exposed to 265–313‐nm monochromatic UV wavelengths and the yield of pyrimidine(6‐4)pyrimidone photoproducts [(6‐4) photoproducts] cyclobutane pyrimidine dimers (dimers) measured by radioimmunoassay. The action spectra for induction these two types DNA damage very similar from 254 302 nm. However, spectrum value (6‐4) photoproduct production was less than half obtained dimer 313‐nm UV. Cells also produced a broad‐spectrum fluorescent sunlamp...
ABSTRACT The molecular and biological consequences of UV-B radiation were investigated by studying five species marine bacteria one enteric bacterium. Laboratory cultures exposed to an artificial source subjected various post-UV irradiation treatments. Significant differences in survival subsequent observed among the isolates, as measured culturable counts. UV-B-induced DNA photodamage was using a highly specific radioimmunoassay measure cyclobutane pyrimidine dimers (CPDs). CPDs determined...
Plants are continually subjected to ultraviolet-B (UV-B) irradiation (290 320 nanometers) as a component of sunlight, which induces variety types damage the plant DNA. Repair two major DNA photoproducts was analyzed in wild-type Arabidopsis thaliana and mutant derivative whose growth sensitive UV-B radiation. In seedlings, repair cyclobutane pyrimidine dimers occurred more slowly dark than light; this photoproduct not affected mutant. Repair, dark, pyrimidine-pyrimidinone(6-4) defective UV-sensitive
drawback to this approach is that it would not stop ocean acidification.It does have many of the drawbacks stratospheric injection sulfur species has.
Chromatin structure is known to be a barrier DNA repair and large number of studies have now identified various factors that modify histones remodel nucleosomes facilitate repair. In response ultraviolet (UV) radiation several are acetylated this enhances the photoproducts by nucleotide excision (NER) pathway. However, molecular mechanism which UV induces histone acetylation allow for efficient NER not completely understood. We recently discovered E2F1 transcription factor accumulates at...
In the prediction of climate change, greatest uncertainty lies in representation clouds. Ice clouds are particularly challenging, and to date there is no accepted method for measuring smaller ice crystals (D < 60 μ m). This study examines sensitivity a global model different assumptions regarding number concentrations small when they allowed affect sedimentation rates. When their relatively high, GCM predicts 12% increase cloud amount 5.5% cirrus coverage globally. produces net forcing −5...
We have implemented a parameterization for forming ice in large-scale cirrus clouds that accounts the changes updrafts associated with spectrum of waves acting within each time step model. This allows us to account frequency homogeneous and heterogeneous freezing events occur model helps determine more realistic number concentrations as well concentrations. The is able fit observations at lowest temperatures tropical tropopause but still somewhat high latitudes between 195°K 215°K. climate...